The lead-acid battery of the UPS power supply is charged to the end. After the two poles are converted into effective materials, and then continue to charge, a large amount of hydrogen and oxygen gas will be generated. H2: O2 was precipitated in a volume of 2: 1. Based on the electrochemical equivalent of hydrogen and oxygen gas, each overcharge 1Ah produces 0.4181L of hydrogen and 0.20907L of oxygen. When the concentration of this mixed gas accounts for 4 in the air, it will explode when it encounters an open flame, which will damage the battery in light, and hurt people and objects in serious cases.
1.Excessive internal pressure of the battery causes the battery case to explode
Due to the working principle of the UPS power battery, during the charging process of the battery, especially due to overcharging at the end of charging, water is decomposed into hydrogen and oxygen, short circuit, severe sulfurization, and the electrolyte temperature rises sharply during charging, which will cause a large amount of water to evaporate. The vent hole of the filling hole cover is blocked. Because too much gas is too late to overflow, the internal pressure of the battery will rise very high, causing the Leoch battery tank to deform first. When the internal pressure reaches a certain pressure, it will come from the battery tank cover joint or other weak points. Burst, this is a physical process. When the internal pressure of the battery is higher than 0.25 MPa, the battery bursts, and the burst location is located at the hot air joint of the slot cover or the corner where the stress is concentrated.
2. The battery exploded when hydrogen meets an open flame
The explosion limit of H2 and O2 mixed gas is 4% -96% of the volume of the mixed gas, and the explosion limit of H2 and air mixed gas is 4% -74% of the volume of the mixed gas. If 80% of the overcharged amount is used to electrolyze water, the H2 content inside the battery is larger than the explosion range. When the hydrogen content in the battery or air accumulates to the explosion limit, an explosion will be formed when it encounters an open flame. Kind of chemical reaction.